stub for general tail call optimization

interpreter/Makefile

 TARGET = main
 LIBS =
 CC = clang++
-CFLAGS = -O3 -x c++ -Wno-write-strings # -g -pg -fstack-usage
+CFLAGS = -g -x c++ -Wno-write-strings # -g -pg -fstack-usage
 
 .PHONY: default all clean
 
@@ -17,7 +17,7 @@ HEADERS = $(wildcard *.h)
 .PRECIOUS: $(TARGET) $(OBJECTS)
 
 $(TARGET): $(OBJECTS)
-	$(CC) $(OBJECTS) -static -static-libgcc -static-libstdc++ -Wl,--stack,16777216 -Wall $(LIBS) -o $@ # -pg -g
+	$(CC) $(OBJECTS) -static -static-libgcc -static-libstdc++ -Wl,--stack,16777216 -Wall -g $(LIBS) -o $@ # -pg -g
 
 clean:
 	-rm -f *.o

interpreter/code.c

@@ -145,6 +145,13 @@ void set_create_thunk_fun(Code* code)
     }
 }
 
+// eval: frame_ptr, frame_ptr
+// start: stack_top_a, stack_top_a
+// otherwise: frame_ptr, stack_top_a
+
+// frame_ptr: first arguments
+// root_frame_ptr: place of the result
+
 void exec(Code* expr, int frame_ptr, int root_frame_ptr)
 {
     if(heap_curr > gc_trigger) gc();
@@ -655,6 +662,7 @@ void eval_fun()
     }
 
     exec(((FunEntry*) thunk->desc)->body, frame_ptr, frame_ptr);
+    //stack_a[frame_ptr] = stack_a[stack_top_a]; 
 }
 
 void eval_prim()

interpreter/main.c

@@ -29,7 +29,7 @@ int main ( int argc, char *argv[] )
     init_desc();
     init_prim();
     
-    char* input = "..\\tests\\Adjoxo.bsapl";
+    char* input = "..\\tests\\queens2.bsapl";
     
     if ( argc == 2 )
     {

interpreter/parse.c

@@ -632,6 +632,8 @@ Code* parseTerm(char **ptr) {
             return (Code*) parseApp(ptr, false, false);
         case 'T': // Tail recursive application
             return (Code*) parseApp(ptr, false, true);
+        case 't': // Tail call application
+            return (Code*) parseApp(ptr, false, true);
         case 'D': // Dynamic application
             return (Code*) parseApp(ptr, true, false);
         case 'S': // Select

precompiler/precompiler.icl

@@ -105,7 +105,8 @@ isLocalVar ctx var = member (unpackVar var) ctx.vars
 appType ctx var | isLocalVar ctx var 
   = "D"
     
-appType {inspine, currentFun} var = if (inspine && unpackVar var == currentFun) "T" "A" // T: tail recursive 
+appType {inspine = True, currentFun} var = if (unpackVar var == currentFun) "T" "A" // T: tail recursive / TODO: "t: tail call "
+appType _ _ = "A" // A: normal call
     
 sLetDef ctx (SaplLetDef var binding) a = a <++ sVarFlag ctx (Local 0 (typeInfo var)) <++ sTerm ctx binding